Unusually high ocean temperatures are being detected around the world more frequently than researchers previously expected, disrupting marine ecosystems and the people who depend on them.

According to the study - entitled "Challenges to natural and human communities from surprising ocean temperatures", published in the Proceedings of the National Academy of Sciences (PNAS) - these warming events, including marine heatwaves, are occurring at nearly double the rate the scientists expected in the Arctic, North Atlantic, eastern Pacific, and off of Australia.

"Across the 65 ecosystems we examined, we expected about six or seven of them would experience these 'surprises' each year," explains the study's lead author, Dr. Andrew Pershing, Chief Scientific Officer at the Gulf of Maine Research Institute.  "Instead, we've seen an average of 12 ecosystems experiencing these warming events each year over the past seven years, including a high of 23 'surprises' in 2016."

In gradually warming areas, the changeover from species that do well in cooler water to the ones that prefer it warm could keep pace.  But ecosystems that are experiencing change much faster, these natural communities are expected to suffer reductions in both biomass and diversity.  And it's not really clear that humans are going to be able to adjust.

"We are entering a world where history is an unreliable guide for decision making," says Dr. Pershing.  "In a rapidly changing world, betting that trends will continue is a much better strategy."